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<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>

<body>
    <form id="form1">
        <input type="text" name="uname" autocomplete="off" />
        <input type="password" name="upwd" />
        <button type="submit">提交</button>
    </form>

    <script>
        // 1. 通过 DOM 操作，获取到 form 表单元素
        var form = document.querySelector('#form1')

        form.addEventListener('submit', function (e) {
            // 阻止表单的默认提交行为
            e.preventDefault()
            // 创建 FormData，快速获取到 form 表单中的数据
            // write here...
            var fd = new FormData(form)
            var xhr = new XMLHttpRequest()
            xhr.open('POST', 'http://www.liulongbin.top:3006/api/formdata')
            xhr.send(fd)

            xhr.onreadystatechange = function () {
                if (xhr.readyState === 4 && xhr.status === 200) {
                    console.log(JSON.parse(xhr.responseText))
                }
            }
        })
    </script>
</body>

</html>